Spin relaxation in the impurity band of a semiconductor in the external magnetic field

TL;DR

This paper investigates various mechanisms of spin relaxation in the impurity band of a 2D semiconductor under an external magnetic field, providing a detailed analysis of phonon-assisted and precession-based processes.

Contribution

It introduces a comprehensive model that accounts for multiple spin relaxation mechanisms in impurity bands, including phonon-assisted transitions and spin precession effects.

Findings

Identifies phonon-assisted transitions as a key relaxation mechanism.

Derives the average spin relaxation rate considering different impurity configurations.

Shows the dependence of relaxation rate on external magnetic field and electron motion.

Abstract

Spin relaxation in the impurity band of a 2D semiconductor with spin-split spectrum in the external magnetic field is considered. Several mechanisms of spin relaxation are shown to be relevant. The first one is attributed to phonon-assisted transitions between Zeeman sublevels of the ground state of an isolated impurity, while other mechanisms can be described in terms of spin precession in a random magnetic field during the electron motion over the impurity band. In the later case there are two contributions to the spin relaxation: the one given by optimal impurity configurations with the hop-waiting time inversely proportional to the external magnetic field and another one related to the electron motion on a large scale. The average spin relaxation rate is calculated.